This invention relates to adapters for releasably attaching and removing syringes to medical injectors, and more particularly to adapters for releasably attaching and removing syringes of various types and sizes to front-loading injectors.
Medical injectors and syringes containing fluid, such as contrast media, are commonly used to inject fluid into a patient in a wide variety of diagnostic imaging procedures. Injectors of the front-loading type are often used in such procedures. U.S. Pat. No. 5,383,858, assigned to the assignee of the present invention and fully incorporated herein by reference, provides a detailed description of injectors of the front-loading type and corresponding syringe designs. One advantage of the front-loading injector of U.S. Pat. No. 5,383,858 is that a syringe can readily be loaded onto and removed from the injector head without the need to disconnect the fluid path from the syringe to the patient. Another advantage of the front-loading injector of U.S. Pat. No. 5,383,858 is that the drive means of the injector head may be disengaged and retracted from the syringe plunger without retracting the syringe plunger, thus substantially reducing the risk of withdrawing fluid from the patient after completion of the diagnostic procedure. This feature is also taught in U.S. Pat. No. 4,677,980, assigned to the assignee of the present invention and fully incorporated herein by reference.
As discussed in U.S. Pat. No. 5,383,858, a syringe used with a front-loading injector requires a specially designed readily releasable mounting mechanism for securing the syringe to the front wall of the injector head and a specially designed readily releasable mounting mechanism for securing the syringe plunger to the piston head of the injector. These required mounting mechanisms oftentimes increase the cost of the syringes and prohibit the use of syringes of other various types, sizes and configurations with front-loading injectors. Thus, it is desirable to design adapters for use with syringes of various types, sizes and configurations to permit use of these syringes with front-loading injectors.
The syringe adapters of the present invention permit use of syringes of various types, sizes and configurations to be used with front-loading injectors, particularly front-loading injectors with or without a removable injector face plate.
In one embodiment of the invention, for use with a front-loading injector having a removable injector face plate, the adapter includes an adapter face plate having a readily releasable mounting mechanism for attaching the adapter face plate to the front wall of the injector head after the injector face plate is removed. A removable pin insertable into the adapter face plate and the front wall of the injector head is provided to prohibit the adapter face plate from rotating with respect to front wall of the injector head.
The adapter further includes a reducing sleeve formed of a reducing base and reducing edge connected to the proximal surface of the reducing base. The edge and base cooperate to form a recess for receiving the syringe distal flange. The adapter further includes a syringe attachment mechanism, for example, locking pivot arms pivotly attached to the proximal surface of the edge. The reducing edge is preferably made from a material having a low coefficient of friction to permit easy and smooth movement of locking pivot arms.
In one embodiment, locking pivot arms are connected by a gear link which permits simultaneous movement of the arms when only one arm is grasped by the operator to move the arms into an opened or closed position. The inside surface of each pivot arm includes first beveled surfaces to permit reception of the syringe flange when pivot arms are in an open position, and second beveled surfaces to engage the distal end of the syringe body when the pivot arms are in a closed position. Pivot arm ends opposite pivot points are cammed to engage and lock around lock point extending from the reducing edge.
The adapter further includes a piston extension to extend the injector drive piston for engagement with the syringe plunger. The piston extension includes means for attaching the extension to the syringe plunger and means for attaching the extension to the injector drive piston. Piston extensions of various diameters and lengths are used to permit use of syringes having various inner diameters and plunger locations.
In another embodiment of the invention, for use with a front-loading injector without a removable face plate, the adapter includes an adapter base from which a readily releasable mounting mechanism extends to permit the attachment to and removal of the adapter from the opening in the front wall of the injector head. All of the other adapter elements previously described may be included in this embodiment.
For injectors with or without removable face plates, the adapter used may also include signal generating means and the injector may include corresponding sensors which cooperate with one another to indicate to the injector that the adapter is properly attached and to automatically calibrate the injector to adjust, for example, flow rate and pressure.